Timepiece dials are made of rigid materials, in particular rigid synthetic materials, to ensure that the display has good resistance and the right appearance.
Moulding methods only allow for tapered surfaces, which restricts the possibility of developing details or even entire dials in relief. It is only possible to place inserts in cylindrical or tapered housings, which means that the inserts have to be bonded or crimped in their housings, to ensure that they are held and positioned properly, particularly in an angular position.
The only possible ways of obtaining undercut surfaces, for holding inserts or for obtaining particular optical effects, thus lie in stacking and bonding several layers or in expensive machining.
CH Patent Application No. 419 978A in the name of FLUCKIGER discloses a dial with notches having bevelled openings on the back, and elongated inserts with elastic lugs clipped thereto.
US Patent Application No. 1 310 523A in the name of EBERHARD discloses a dial with a base comprising conical inserts on the back, into which slit feet, comprised on the back of the display component, are clipped.
CH Patent Application No. 393 191A in the name of LE PRELET discloses a dial comprising slots, into which fitted signs, comprising feet and riveted to the back of the dial, are inserted in conical or bevelled openings.
EP Patent Application No. 0257 453A in the name of TISSOT discloses a single piece dial having a middle part made of natural mineral material, comprising housings in which cabochons containing cut stones are set.
CH Patent Application No. 260 123A in the name of BEYELER also discloses a dial with cut stones mounted in a cabochon or mounted through the back of the dial and held by undercut surfaces.
JP Patent Application No. 58 124979A in the name of SEIKO discloses the bonding of stones in cabochons, as an alternative to setting stones in cabochons.
JP Patent Application No. 2005 049277A in the name of KAWAGICHIKO SEIMITSU discloses a relief dial with moulded undercut surfaces, wherein the decoration of the display signs is achieved by pad printing in several stages.